Search results for "dehydration"
showing 10 items of 134 documents
Nature of sterols affects plasma membrane behavior and yeast survival during dehydration.
2011
International audience; The plasma membrane (PM) is a main site of injury during osmotic perturbation. Sterols, major lipids of the PM structure in eukaryotes, are thought to play a role in ensuring the stability of the lipid bilayer during physicochemical perturbations. Here, we investigated the relationship between the nature of PM sterols and resistance of the yeast Saccharomyces cerevisiae to hyperosmotic treatment. We compared the responses to osmotic dehydration (viability, sterol quantification, ultrastructure, cell volume, and membrane permeability) in the wild-type (WT) strain and the ergosterol mutant erg6Δ strain. Our main results suggest that the nature of membrane sterols gover…
Dehydration of mildronate dihydrate: a study of structural transformations and kinetics
2014
The dehydration of mildronate dihydrate (3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propionate dihydrate) was investigated by powder X-ray diffraction, thermal analysis, hot-stage microscopy, water sorption–desorption studies and dehydration kinetic studies. It was determined that mildronate dihydrate dehydrated in a single step, directly transforming into the anhydrous form. In order to understand the reasons for a one step dehydration mechanism, crystal structures of dihydrate, monohydrate and anhydrous forms were compared, proving the similarity of the dihydrate and anhydrous forms. In order to understand the reasons for molecule reorganization during dehydration, the energy of the anhydrous …
Sugar-induced stabilization of the monoolein Pn3m bicontinuous cubic phase during dehydration
2001
To explore the molecular mechanism of the protective function of sugars on cubic lipidic systems, the mesomorphic properties of the monoolein-water system, dehydrated in the presence of a series of sugars, have been studied by osmotic stress experiments. Two bicontinuous inverse cubic structures $(Pn3m$ and $\mathrm{Ia}3d)$ and a lamellar ${L}_{\ensuremath{\alpha}}$ phase form under dehydration in pure water. In sugar solutions, the $\mathrm{Pn}3m$ phase shows an extraordinary stability: as a function of sugar concentration, the lattice parameter decreases to very low values, but no phase transitions occur. Instead, the $\mathrm{Pn}3m$ to $\mathrm{Ia}3d$ phase transition is obtained by equi…
The response ofAsterochloris erici(Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach
2013
The study of desiccation tolerance of lichens, and of their chlorobionts in particular, has frequently focused on the anti- oxidant system that protects the cell against photo-oxidative stress during dehydration/rehydration cycles. In this study, we used proteomic and transcript analyses to assess the changes associated with desiccation in the isolated phycobiont Aste- rochloris erici. Algae were dried either slowly (5-6 h) or rapidly (<60 min), and rehydrated after 24 h in the desiccated state. To identify proteins that accumulated during the drying or rehydration processes, we employed two-dimensional (2D) difference gel electrophoresis (DIGE) coupled with individual protein identificatio…
A relationship between tolerance to dehydration of rice cell lines and ability for ABA synthesis under stress
2005
Plant dehydration is commonly caused by some adverse environmental conditions such as salinity, drought and freezing. As the plant hormone abscisic acid (ABA) is involved in responses to water stress, we studied its putative relationship with the degree of tolerance to these abiotic stresses. For this purpose we used cell lines that had been established from mature embryos of rice (Oryza sativa L, cvs. Bahia and Bomba), and selected by their high (L-T) or low (L-S) levels of tolerance to each type of stress. Tolerance of rice calli to either osmotic, saline, or freezing stress was generally improved by a previous treatment with ABA. This ABA effect was evident in those callus lines with low…
Reversible dehydration polymerization of terephthalate bridged [{Cu2(2,2′-bpy)2(tp)(H2O)3(NO3)}·H2O·NO3]2
2006
The title compound is the first example of a molecular magnet sponge, which exhibits a carboxylate-assisted unique reversible dehydrative polymerization–rehydrative monomerization phenomenon.
Physical pre-treatment of plums (Prunus domestica). Part 2. Effect on the quality characteristics of different prune cultivars
2002
The effects of an alternative physical pre-treatment for enhancing the drying rate of different plums (Stanley, Angeleno(R), and Empress), are evaluated by means of the principal chemical parameters and by skin colour. The pre-treatment consists of the superficial abrasion of the plums' peels using an inert abrasive material to remove the cuticular waxy layer, the limiting factor for moisture loss. The drying process was carried out at 60 C to reduce the plums' quality loss, the latter being assessed by analysing the changes in skin colour, sugars by HPLC, total phenols, total anthocyanins, and reactive substances to the vanillin-HCl reagent. The proposed physical pre-treatment, without sig…
Photocatalytic Gas-Solid Propene Hydration and Liquid-Solid Glycerol Dehydration by using Keggin Heteropolyacids Supported on TiO2
2015
Photo)catalytic propylene hydration to 2-propanol and glycerol dehydration to acrolein reactions were carried out by using Keggin heteropolyacids (HPAs) supported on TiO2. Binary materials have been prepared by impregnation of H3PW12O40, H3PMo12O40 and H4SiW12O40, on TiO2 Evonik P25. Moreover, a binary material consisting of H4SiW12O40 and TiO2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-rayand (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform infrared spectroscopy…
Proteome analysis of leaves of the desiccation-tolerant grass, Sporobolus stapfianus, in response to dehydration.
2011
Drought and its affects on agricultural production is a serious issue facing global efforts to increase food supplies and ensure food security for the growing world population. Understanding how plants respond to dehydration is an important prerequisite for developing strategies for crop improvement in drought tolerance. This has proved to be a difficult task as all of the current research plant models do not tolerate cellular dehydration well and, like all crops, they succumb to the effects of a relatively small water deficit of -4MPa or less. For these reasons many researchers have started to investigate the usefulness of resurrection plants, plants that can survive extremes of dehydratio…
Propan-2-ol dehydration on H-ZSM-5 and H-Y zeolite: a DFT study
2012
The catalytic dehydration of propan-2-ol over H-Y and H-ZMS-5 aluminated zeolite models, mimicking both internal cavities and external surfaces, was studied by DFT calculations to investigate the reaction mechanism. After the adsorption of propan-2-ol on the zeolite, the dehydration mechanism starts with alcohol protonation, occurring by one acidic –OH group of the zeolite fragment, followed by a concerted β-elimination to give propene. The catalytic activity is affected by the size of the zeolite cavity, which is larger in the H-Y than in the H-ZMS-5 zeolite. The adsorption energy of the reagent, as an example, decreases in the order: H-Y cavity ≃ H-ZMS-5 surface > H-ZMS-5 cavity, pointing…